C-peptide of human insulin is

Options

A. a part of mature insulin molecule
B. responsible for formation of disulphide bridges
C. removed during maturation of pro-insulin to insulin
D. responsible for its biological activity

Explanation

**Step-by-Step Solution:**

1. **Understanding Pro-insulin:**
- Human insulin is initially produced as pro-insulin, which is an immature form of insulin.
- Pro-insulin consists of three chains: the A chain, B chain, and C chain.

2. **Role of C-peptide:**
- The C-peptide is a connecting peptide found in pro-insulin.
- It is important for the proper folding and stabilization of the pro-insulin structure.

3. **Maturation Process:**
- The pro-insulin undergoes a maturation process to become fully functional insulin.
- This maturation occurs in the pancreas and involves the cleavage of the C-peptide.

4. **Formation of Mature Insulin:**
- Mature insulin consists only of the A chain and B chain.
- The A chain contains 21 amino acids, and the B chain contains 30 amino acids.
- The C-peptide is removed during this conversion process.

5. **Conclusion:**
- Therefore, the C-peptide of human insulin is removed during the maturation of pro-insulin to insulin.

**Final Answer:**
The C-peptide of human insulin is removed during the maturation of pro-insulin to insulin.

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